Known dishwashers typically include a motor for driving a circulation pump, a drain solenoid for diverting water so that the water accumulated in the dishwasher can be pumped out of the washing chamber, a water valve for controlling the flow of water into the dishwasher, and a heating element for heating the water and drying the dishes. In an exemplary dishwashing cycle, the circulation pump motor is energized, and then the water valve is opened so that water flows into the dishwasher and is circulated by the circulation pump. Once sufficient water has been supplied to the dishwasher, the water valve is closed but the circulation pump motor continues to operate to circulate the supplied water. After a predetermined period of time, the heating element is energized while the circulation pump motor remains energized so that heated water is circulated within the washing chamber. The heating element is then deenergized, and the drive solenoid is energized to open the drain valve while the circulation pump motor remains energized. As a result, water flows out from the dishwasher. The drive solenoid is then deenergized so that the drain valve closes, and the circulation pump motor remains energized. The above described sequence is repeated during the wash portion of the dishwashing cycle. The sequence may be repeated, for example, four to seven times depending on the wash cycle selected.
In an all-electronic control system, the circulation pump motor, drain solenoid, water valve, and heating element typically are controlled by separate timers and relays. For example, a timer for the circulation pump motor supplies a timing signal to the motor relay, and based on the timing signal, the motor relay controls energization and deenergization of the circulation pump motor. Similar controls are provided for each of the drain solenoid, the water valve, and the heating element.
If the separate timers and relays for the above described components could be eliminated, the component cost and assembly time associated with fabrication of known dishwashers could be reduced. In addition, by eliminating such separate components, the maintenance and repair costs associated with known dishwashers also possibly could be reduced. Of course, in reducing the cost of the dishwasher, the operation of the dishwasher should not be adversely affected.